Ordinary removable dentures, dental plates, and the like, comprise teeth mounted in a suitable plate or base. Dentures function as a substitute for missing teeth and serve as a replacement for all or a portion of the teeth ordinarily found in the oral cavity. Although dentures generally are skillfully prepared, often they do not fit perfectly. Moreover, no matter how satisfactory at first, after a period of time the fit of the denture becomes loose and imperfect due to natural shrinkage and changes in the gums, mucous tissues, and the like. Loose and imperfectly fitted dentures usually are corrected and stabilized by the use of a denture adhesive. Denture adhesives are used to fill the interstices between the dentures and the gums or tissues. Prior to placement of the denture in the oral cavity, a denture adhesive is applied to the denture-plate surface which, for a perfect fit, should uniformly contact the gums and mucous tissues. The denture adhesive is formulated not only for its adherent properties, but also to provide a cushion or gasket between the denture and the gums or tissues, thereby positioning the denture securely in the oral cavity.
Requirements and characteristics for a satisfactory denture adhesive composition are many and are dictated by numerous factors. Desirably, one daily application of such a composition should function as an effective means for insulating, cushioning, and securely positioning the denture. The composition should retain its characteristics and properties in the typical powder and cream forms during storage under various climatic conditions taste; optionally provide antiseptic and germicidal properties for preventing or inhibiting the growth of organisms ordinarily found in the mouth; and function as an agent for prevention of putrefaction or malodorous decomposition of foods or secretions lodging beneath or adjacent to the denture. The adhesive material must be capable of imbibing water and saliva and swelling, so as to essentially fill the interstices between the denture and the gum or mucous tissues. The adhesive should not attack or damage the denture, as by causing a crazing of the denture-plate material. Additionally, the adhesive should be stable to bacteria, molds and enzyme systems found in the oral cavity, and have a pH that is nonirritating to the oral mucosa, generally 5-8.5, preferably a pH around 7.0. The mechanical strength of the adhesive mass, be it gel or colloid, formed by imbibition of water should be great enough to securely maintain the position of the denture under normal use, and not so great as to make denture removal difficult when desired, or as to damage or injure the gums, tissues or denture upon removal.
There has been a considerable effort made over many years to develop improved denture adhesives. Both synthetic and natural polymers and gums have been used singly, in combination, and in combination with various additives.
European Patent 64,672 to Dhabhar and Schmidt, published Nov. 17, 1982, relates to a hydrophilic denture adhesive containing an adhesive polymeric fraction comprising CMC and poly(ethylene oxide) in a hydrophilic vehicle.
European Patent Application 140,486 to A. J. Desmaris, filed Jul. 31, 1984 relates to denture adhesive compositions containing a hydrophobically modified water-soluble polymer, alone or admixed with an alkali metal salt of CMC. Hydrophobically modified hydroxyalkyl celluloses and copolymers of ethylene oxide and long chain epoxyalkanes are preferred for use in the compositions.
U.S. Pat. No. 4,280,936 to Dhabhar, Heyd and Schmidt (issued Jul. 28, 1981), relates to improved denture adhesives containing a specified ratio of CMC and poly(ethyleneoxide) in a mineral oil base.
U.S. Pat. No. 4,474,902 to Dhabhar and Schmidt (issued Oct. 2, 1984), relates to improved denture adhesives containing karaya gum in a hydrophilic vehicle. See also U.S. Pat. No. 4,514,528 (issued Apr. 30, 1985) specified ratio of CMC and poly(ethyleneoxide) in a mineral oil base.
U.S. Pat. No. 4,474,902 to Dhabhar and Schmidt (issued Oct. 2, 1984), relates to improved denture adhesives containing karaya gum in a hydrophilic vehicle. See also U.S. Pat. No. 4,514,528 (issued Apr. 30, 1985) and U.S. Pat. No. 4,518,721 (issued May 21, 1985) to these same inventors, relating, respectively, to improved denture adhesives containing adhesive polymeric fractions consisting of admixtures of partial salts of lower alkylvinyl ether maleic anhydride-type copolymers with CMC or poly(ethyleneoxide), as well as denture adhesives containing CMC and poly(ethyleneoxide). See also U.S. Pat. No. 4,522,956 (issued Jun. 11, 1985) to Dhabhar and Schmidt relating to improved denture adhesives containing poly(ethyleneoxide) as the sole adhesive component in a hydrophilic vehicle comprising certain polyethylene glycols.
Other denture adhesives are described in U.S. Pat. Nos. 4,530,942 (issued Jul. 23, 1985); 4,542,168 (issued Sep. 17, 1985); and 4,569,955 (issued Feb. 11, 1986).
U.S. Pat. No. 4,529,748 to H. G. P. Wienecke (issued Jul. 16, 1985), relates to dental prosthesis adhesives formed from film-forming substances such as various cellulose derivatives, acrylate polymers, methacrylate polymers, and other film-providing substances.
U.S. Pat. No. 4,138,477 to Gaffar (issued Feb. 6, 1979) discloses oral compositions to control mouth odor containing zinc-polymer combinations formed from zinc reacted with an anionic polymer containing carboxylic, sulfonic and/or phosphonic acid radicals.
Although many different approaches have been taken to formulate denture adhesives, there is still the need to develop adhesives which hold well and are more aesthetically pleasing.
Yet, the search continues for denture adhesives that will provide the above-described characteristics and, importantly, will maintain the secure fit of the denture.
In accordance with the present invention, improved aesthetic characteristics are obtained in a denture adhesive composition by using a hydrophilic adhesive powder and a liquid vehicle that cures to a peelable solid.
It is an object of the present invention to provide improved denture adhesives which are easy to manufacture and that will be stable over prolonged periods in the oral cavity, yet will allow easy removal of the denture on demand.
It is a further object of the present invention to provide denture adhesive compositions which provide the user with greater ease of removal of the adhesive from the dentures.
It is a further object to provide such adhesives using toxicologically-acceptable, palatable materials.
It is another object herein to provide adhesives that perform well in the presence of moisture, particularly in the presence of body fluids such as saliva, perspiration and blood.
These and other objects are secured by the present invention, in the manner disclosed hereinafter.
All percentages and ratios herein are by weight and all measurements are made at 25.degree. C. unless otherwise specified.